The mineralocorticoid hormones (MCH) secreted by the adrenal cortex regulate body electrolyte composition and blood pressure: 1) All the major components of the MCH pathway, (Deoxycorticosterone (DOC), Corticosterone (B), 18 Hydroxy B (18OHB), and aldosterone), can be measured in blood and their metabolites in urine. Measurements of these hormones under defined conditions will be examined for evidence of an adrenal role in hypertensive disorders. Increased sensitivity of this pathway to an endogenous increase of renin (upright posture) and a 4-hour infusion of ACTH (Cortrosyn) 0.95 mU/min will be examined in hypertensive patients with normal and low plasma renin concentration (PRC). The classification of sub-types of primary aldosteronism by measurement of plasma aldosterone concentration response to the upright posture will be further examined as a mechanism to distinguish an aldosterone producing adenoma from adrenocortical hyperplasia; and the 4-hour ACTH infusion (0.95 mU) will be performed to determine the sensitivity/response of the MCH pathway. 2) During these procedures measurement of the individual hormones will permit assessment of acceleration or retardation of biosynthesis at specific sites. 3) During these maneuvers the adrenal mixture will vary and the influence of such change on free aldosterone and DOC concentrations will be assessed. 4) New mineralocorticoid hormones are suggested in two patients with low aldosterone levels and suppressed renin with evidence of increased biological MCH activity.